bcachefs: Fix for bad stripe pointers

The allocator usually doesn't increment bucket gens right away on
buckets that it's about to hand out (for reasons that need to be
documented), instead deferring that to whatever extent update first
references that bucket.

But stripe pointers reference buckets without changing bucket sector
counts, meaning we could end up with a pointer in a stripe with a gen
newer than the bucket it points to.

Fix this by adding a transactional trigger for KEY_TYPE_stripe that just
writes out the keys in the alloc btree for the buckets it points to.

Also - consolidate the code that checks pointer validity.
Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

fs/bcachefs/alloc_background.c

@@ -497,8 +497,6 @@ static void bch2_bucket_clock_init(struct bch_fs *c, int rw)
  * commands to the newly free buckets, then puts them on the various freelists.
  */
 
-#define BUCKET_GC_GEN_MAX	96U
-
 /**
  * wait_buckets_available - wait on reclaimable buckets
  *

fs/bcachefs/alloc_background.h

@@ -13,6 +13,9 @@ struct bkey_alloc_unpacked {
 #undef  x
 };
 
+/* How out of date a pointer gen is allowed to be: */
+#define BUCKET_GC_GEN_MAX	96U
+
 /* returns true if not equal */
 static inline bool bkey_alloc_unpacked_cmp(struct bkey_alloc_unpacked l,
 					   struct bkey_alloc_unpacked r)

fs/bcachefs/btree_types.h

@@ -591,6 +591,7 @@ static inline bool btree_iter_is_extents(struct btree_iter *iter)
 #define BTREE_NODE_TYPE_HAS_TRANS_TRIGGERS		\
 	((1U << BKEY_TYPE_EXTENTS)|			\
 	 (1U << BKEY_TYPE_INODES)|			\
+	 (1U << BKEY_TYPE_EC)|				\
 	 (1U << BKEY_TYPE_REFLINK))
 
 enum btree_trigger_flags {

fs/bcachefs/btree_update_leaf.c

@@ -337,8 +337,9 @@ static inline bool iter_has_trans_triggers(struct btree_iter *iter)
 
 static inline bool iter_has_nontrans_triggers(struct btree_iter *iter)
 {
-	return (BTREE_NODE_TYPE_HAS_TRIGGERS &
-		~BTREE_NODE_TYPE_HAS_TRANS_TRIGGERS) &
+	return (((BTREE_NODE_TYPE_HAS_TRIGGERS &
+		  ~BTREE_NODE_TYPE_HAS_TRANS_TRIGGERS)) |
+		(1U << BTREE_ID_EC)) &
 		(1U << iter->btree_id);
 }